So ever since I got the D Ive had a weird thunk sound coming from the front of the rig. Basically every time I put the key in the ignition and turn it to the "start" position just before cranking there is a big think sound coming from the drivers side in the engine bay. Then when I start it and go to move and let off the brake it makes the same sound again.

Could this be the abs pump box doing this?
Can you drain the abs and put new fluid in it?

 

I would get a buddy over to cycle the key while the hood is open so you can listen better as to where the sound is coming from. Now the abs shouldn't make that noise, even if it has failed.........Could be a stuck caliper releasing though.

 

I can feel the vibration in the brake pedal...it only happens at start up. Never any other time. But i have been wondering if this has something to do with my braking problems that I have been having...

 

sounds like you've got your self a nice little gremlin there. What other braking problems are you having? My guess is that they are probably related.

 

I have posted a couple of different posts where it seems like I have brake fade. I have found that if I pump my brakes a couple of times before I start the D that I have good brakes the whole time I am going. But if I dont then I have to put the pedal 2/3 down before it will even start to engauge. I want to bleed the brakes and see if it helps but I think I have a bad line somewhere...

 

Well are you having to add brake fluid at all?

 

Does it pull to one side when braking?
Does the thunk still happen when you don't push the pedal down?
It could be a loose bolt on the caliper or the pad is not sitting flush.
Maybe even a bad motor/tranny mount, that gives a thunk sound.
Mosty when you shift from P to D.

 

No I dont have to add any fluid. When I said a bad line I mean the ballon effect you can get from a stretched line.

It doesn't pull no.
Yea when I start it no matter what it makes that sound.
But the weird thing is how iregular it really is. I think it may be tied to something electrical and with the brakes...truely a bug in the system somewhere...

 

I'm wondering if you have a collapsed line that is keeping fluid from getting to the brakes until you apply enough pressure to get through it.

 

I was told that today when I took it in to my neighbor's shop. Wish I would of thought of that...
He is almost certain that it is a collapsed line...great. Well at least it stops for now. That explains the braking problem no worries, but he has no clue what this sound is. I may call and ask the tec at the dodge dealership if he has any idea. But I wont take it in cause they charge $70 just to open the hood.